Trigger with adjustable screw and stud therein



TRIGGER WITH ADJUSTABLE SCREW AND STUD THEREIN Filed June 27, 1962INVENTOR. [DJ/144R!) L. MORROW WWW United States Patent 3,142,926TRIGGER WITH ADJUSTABLE SCREW AND STUD THEREIN Edward L. Morrow,Fairfield, Conn., assignor to Olin Mathieson Chemical Corporation, acorporation of Virginia Filed June 27, 1962, Ser. No. 205,612 Claims.(Cl. 4269) This application relates to the method and means foradjusting the trigger assembly in a firearm.

The invention more specifically relates to the provision of a noveladjustable releasing stud for the trigger in a firearm trigger assembly.

In a firearm trigger assembly having a plurality of pivotally mountedand relatively movable elements including a trigger, a sear and ahammer; a buildup of tolerances occurs which necessitates and ajustmentbetween the trigger and the sear to render the structure operative.

The tolerance buildup occurs because it is impossible to bore the holesfor the pivotal connections with exact accuracy. The pivot pins andother elements found in such structures are furthermore not perfectlydimensioned. Thus, the plus and minus tolerances accumulate so that somemeans must be devised to adjust the tolerances at final assembly. Thisproblem becomes more acute in those trigger assemblies in which thepivoted sear is mounted on a pivotal sensing element, such as in thedevice disclosed in Brunelle Patent 2,922,241, since such a structureintroduces additional pivotal connections.

It has been the practice in the art to completely assemble the triggerassembly, measure the tolerance between the trigger and the sear, andthen disassemble the structure to adjust the tolerance. This is done byinitially providing the trigger with a raised integral lug, or a steppedportion as in Patent 2,922,241, in the area where the trigger engagesthe sear. Upon disassembly the lug or step is filed down by hand toprovide an acceptable operative tolerance between the trigger and thesear.

It is therefore an object of this invention to provide novel adjustingmeans for a trigger assembly which can be readily adjusted at finalassembly; thereby eliminating the necessity of assembly, measurement,adjustment, and then final assembly which is a time consuming andtedious operation.

It is a further object of this invention to provide a trigger assemblywith adjusting means which can be adjusted at final assembly and thenlocked in place to prevent tampering with the adjustment.

These and other objects and advantages of this invention will becomemore readily apparent from the following detailed description and thedrawings in which:

FIG. 1 is a side view partly in section showing the trigger assembly ofthis invention.

FIG. 2 is a detailed side view of the trigger and adjusting means.

Referring now to FIG. 1 of the drawing, there is shown a trigger housinggenerally indicated 1. A trigger 2 is pivotally mounted in the housingby means of a pivot pin 3. The trigger 2 is provided with a stud 4 whichengages a projection 5 on a scar 6. The sear 6 is pivotally mounted bymeans of pivot pin 7 on a sensing lever 8. Sensing lever 8 is in turnpivotally mounted in the trigger housing 1 by means of a pivot pin 9.Sear 6 has a hook portion 10 which is engageable with a hook portion 11of hammer 12. Hammer 12 is pivotally mounted in trigger housing 1 bymeans of a pivot pin 13.

In operation, trigger 2 is squeezed manually and I0- tates about itspivot 3. Stud 4 engages projection 5 on sear 6 to rotate the sear in acounterclockwise direction away from hammer 12. As the sear is rotated,hook portion 10 on the sear becomes disengaged from the hook portion 11on the hammer 12 and the hammer is released. Spring means (not shown)drive the hammer 12 toward impacting engagement with a cartridgepositioned in the firearm chamber (not shown).

It is apparent that the engagement between stud 4 on the trigger andprojection 5 on the sear requires careful adjustment if the device is tobe operative. If the tolerance between the stud 4 and projection 5 istoo great, the gun will not fire. If the tolerance is too close, thetrigger will be too sensitive.

To provide for the correct tolerance adjustment between stud 4 and theprojection 5, the novel arrangement shown in detail in FIG. 2 isprovided. Trigger 2 is bored to provide an opening 14 adapted toaccommodate a narrow shank portion 15 which is integral with stud 4. Theopening 14 is tapped to provide screw threads 16 approximately halfwayinto opening 14. A special screw 17 having a head 18 and a tapered neck19 is threaded into opening 14. Stud 4 is pressed into opening 14 fromthe other end. The elements which comprise the trigger assembly areassembled in the manner indicated above. The assembly is then adjustedby pulling the trigger and turning screw 17 inwardly toward stud 4 untilhammer release occurs. Screw 17 is then advanced an additional /8 turnand Locktite or other equivalent locking composition is applied to thescrew. Locktite is a single component polyester resin sold by theAmerican Sealants Company of Hartford, Connecticut. Head 18 is thenbroken off at the tapered neck portion 19.

It is apparent that this invention provides a novel and convenientstructure for adjusting the trigger in a trigger assembly, which allowsthe adjustment to be accurately made after final assembly of thestructure. The device disclosed herein, while being relatively simple,eliminates the necessity of assembling the structure, takingmeasurements, disassembling the structure, filing down a projection onthe trigger, and then making a final assembly.

This invention has been described in detail with reference to thespecific embodiment shown in the drawings; however, it is contemplatedthat modifications in structure and design can be made which will bewithin the scope of the appended claims.

I claim:

1. In a trigger assembly including a pivotally mounted sear engageablewith a pivotally mounted hammer, a trigger having an opening therein, astud pressed into one end of said opening, said stud having an enlargedhead portion engageable with said sear, screw means threaded in theother end of said opening engageable with said stud to move saidenlarged head portion to- Ward said sear as the screw means is rotated.

2. An adjustable trigger for firearms comprising in combination atrigger having an opening therein extending from a top surface through abottom surface of the trigger, a stud having an enlarged head portionextending above the top surface of the trigger and a shank portionpressed into said opening, and screw means having a body portionthreaded into said opening engageable with said stud and having a headportion.

3. The device of claim 2 in which the body portion and the head portionof said screw means are joined by a portion of reduced diameter so thatthe head portion can be easily removed after final adjustment.

4. In a trigger assembly including a pivotally mounted sear engageablewith a pivotally mounted hammer, a pivotally mounted trigger having anopening extending from the top surface thereof through the bottomsurface thereof, a stud including an enlarged head portion extendingabove said top surface and a reduced shank portion pressed into one endof said opening, screw means threaded into the other end of said openingand having a head extending below said bottom surface, said screwReferences Cited in the file of this patent UNITED STATES PATENTSLaudensack Feb. 9, 1937 Barnett June 28, 1949 Hoard Apr. 24, 1951 CutlerJuly 3, 1951 Brunelle Jan. 26, 1960

1. IN A TRIGGER ASSEMBLY INCLUDING A PIVOTALLY MOUNTED SEAR ENGAGEABLEWITH A PIVOTALLY MOUNTED HAMMER, A TRIGGER HAVING AN OPENING THERIN, ASTUD PRESSED INTO ONE END OF SAID OPENING, SAID STUD HAVING AN ENLARGEDHEAD PORTION ENGAGEABLE WITH SEAR, SCREW MEANS THREADED IN THE OTHER ENDOF SAID OPENING ENGAGEABLE WITH SAID STUD TO MOVE SAID ENLARGED HEADPORTION TOWARD SAID SEAR AS THE SCREW MEANS IS ROTATED.